Among the conventionally-known mobile power generator apparatus are ones in which the power generator is mounted in a frame, and in which left and right wheels are attached to lower end portions of left and right side walls of the frame for carrying the power generator and a pulling handle is attached to an upper end portion of the frame. Such portable power generator apparatus can be moved via the moving wheels by a user or human operator gripping a grip portion of the pulling handle to lift the handle. One example of the mobile power generator apparatus of the aforementioned type is disclosed in Japanese Patent Application Laid-Open Publication No. 2006-271122.
In the mobile power generator apparatus disclosed in the 2006-271122 publication, an axle extends through the interior of the frame, the left and right wheels are mounted on left and right end portions, respectively, of the axle. If the axle is provided to extend through a relatively high interior region of the frame, it would be difficult to secure, inside the frame, a space for accommodating therein the power generator due to the presence of the axle. Thus, in the disclosed mobile power generator apparatus, the axle is provided to extend through a relatively low interior region of the frame, so as to secure a sufficient space for accommodating therein the power generator without being hindered by the axle. However; in the case where the axle extends through a relatively low interior region of the frame, it is necessary that the left and right wheels have a relatively small outer diameter, in order to reduce the overall height of the portable power generator apparatus.
Generally, where the mobile power generator apparatus is used on an uneven surface, it can move more smoothly if the left and right wheels have a greater outer diameter. With the left and right wheels having a great outer diameter, however, the centers of the left and right wheels would be located at a high position, and thus, the axle has to be provided to extend through a relatively high interior region of the frame. In such a case, however, it is difficult to secure, inside the frame, a space for accommodating therein the power generator due to the presence of the axle. Further, if the left and right wheels have a great outer diameter, left and right side walls of the frame are covered with the left and right wheels, which would make it difficult to form, in left and right side walls of the frame, openings to be used for maintenance of the power generator.